Dynamic rupture process of the 2017 Mw6.5 Jiuzhaigou earthquake based on stress parameters inferred from kinematic slip inversion

Chen XF(陈晓非)3; Feng Hu1; Yong Zhang2; Xiurong Xu1

2020-04

10.1016/j.tecto.2020.228441

TECTONOPHYSICS   影响因子和分区

0040-1951

1879-3266

Heterogeneous initial stresses are extremely important in understanding the physics of earthquake rupture processes. We propose a method to estimate heterogeneous initial stresses by comparing the slip from dynamic rupture simulations and the input joint inversion result and apply it to the 2017 Mw 6.5 Jiuzhaigou earthquake, which occurred in the intersection area of the Minjiang, Tazang and Huya faults, in Sichuan Province, China, with the slip distributed on two distinct left-lateral strike-slip faults as shown in previous geodetic and seismic joint inversion. We use the seismic efficiency empirical relation to infer the average stress, and the average stress drop is estimated using the static stress drop. With the angle of the maximum principal stress and the nucleation fault determined from the relocated aftershocks, different principal stresses are calculated with different combinations of average stress and average stress drop. The initial normal and residual stresses can be determined using the projection of the principal stresses. The initial shear stresses are generated by adding the residual stress and the heterogeneous stress drop, which is generated by a set of Gaussian random numbers with a given mean and the variance, and mapped one-by-one with the given slip on the fault so that the area with a large slip has a large stress drop. By comparing the slip from dynamic rupture simulations and the input joint inversion result, we show that the case with a 36 MPa average stress and 2.1 MPa average stress drop provides the best-fitting slip snapshots. The dynamic Coulomb stress change shows that the 2017 Mw 6.5 Jiuzhaigou earthquake could bring the southeast of the Tazang fault and the middle of the Minjiang fault closer to failure. This work provides a new insight to understand the initial stresses of nature earthquakes.

The 2017 Jiuzhaigou earthquake Initial stress generation Dynamic rupture modeling

SCI ; EI

英语

第一

National Natural Science Foundation of China[41774044]

Geochemistry & Geophysics

Geochemistry & Geophysics

WOS:000536201000003

ELSEVIER

20201608422842

Residual stresses ; Strike-slip faults ; Drops ; Fault slips ; Random errors ; Earthquakes

Seismology:484 ; Earthquake Measurements and Analysis:484.1

GEOSCIENCES

Web of Science

1.University of Science and Technology of China
2.Peking University
3.Department of Earth and Space Sciences, Southern University of Science and Technology, Shenzhen, China

Chen XF,Feng Hu,Yong Zhang,et al. Dynamic rupture process of the 2017 Mw6.5 Jiuzhaigou earthquake based on stress parameters inferred from kinematic slip inversion[J]. TECTONOPHYSICS,2020,784.

Chen XF,Feng Hu,Yong Zhang,&Xiurong Xu.(2020).Dynamic rupture process of the 2017 Mw6.5 Jiuzhaigou earthquake based on stress parameters inferred from kinematic slip inversion.TECTONOPHYSICS,784.

Chen XF,et al."Dynamic rupture process of the 2017 Mw6.5 Jiuzhaigou earthquake based on stress parameters inferred from kinematic slip inversion".TECTONOPHYSICS 784(2020).